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comparison libtommath/bn_mp_mul_d.c @ 1436:60fc6476e044

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Update to libtommath v1.0
author Matt Johnston <matt@ucc.asn.au>
date Sat, 24 Jun 2017 22:37:14 +0800
parents 5ff8218bcee9
children 8bba51a55704
comparison
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1435:f849a5ca2efc 1436:60fc6476e044
1 #include <tommath.h> 1 #include <tommath_private.h>
2 #ifdef BN_MP_MUL_D_C 2 #ifdef BN_MP_MUL_D_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
4 * 4 *
5 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
10 * additional optimizations in place. 10 * additional optimizations in place.
11 * 11 *
12 * The library is free for all purposes without any express 12 * The library is free for all purposes without any express
13 * guarantee it works. 13 * guarantee it works.
14 * 14 *
15 * Tom St Denis, [email protected], http://math.libtomcrypt.com 15 * Tom St Denis, [email protected], http://libtom.org
16 */ 16 */
17 17
18 /* multiply by a digit */ 18 /* multiply by a digit */
19 int 19 int
20 mp_mul_d (mp_int * a, mp_digit b, mp_int * c) 20 mp_mul_d (mp_int * a, mp_digit b, mp_int * c)
22 mp_digit u, *tmpa, *tmpc; 22 mp_digit u, *tmpa, *tmpc;
23 mp_word r; 23 mp_word r;
24 int ix, res, olduse; 24 int ix, res, olduse;
25 25
26 /* make sure c is big enough to hold a*b */ 26 /* make sure c is big enough to hold a*b */
27 if (c->alloc < a->used + 1) { 27 if (c->alloc < (a->used + 1)) {
28 if ((res = mp_grow (c, a->used + 1)) != MP_OKAY) { 28 if ((res = mp_grow (c, a->used + 1)) != MP_OKAY) {
29 return res; 29 return res;
30 } 30 }
31 } 31 }
32 32
46 u = 0; 46 u = 0;
47 47
48 /* compute columns */ 48 /* compute columns */
49 for (ix = 0; ix < a->used; ix++) { 49 for (ix = 0; ix < a->used; ix++) {
50 /* compute product and carry sum for this term */ 50 /* compute product and carry sum for this term */
51 r = ((mp_word) u) + ((mp_word)*tmpa++) * ((mp_word)b); 51 r = (mp_word)u + ((mp_word)*tmpa++ * (mp_word)b);
52 52
53 /* mask off higher bits to get a single digit */ 53 /* mask off higher bits to get a single digit */
54 *tmpc++ = (mp_digit) (r & ((mp_word) MP_MASK)); 54 *tmpc++ = (mp_digit) (r & ((mp_word) MP_MASK));
55 55
56 /* send carry into next iteration */ 56 /* send carry into next iteration */
72 72
73 return MP_OKAY; 73 return MP_OKAY;
74 } 74 }
75 #endif 75 #endif
76 76
77 /* $Source: /cvs/libtom/libtommath/bn_mp_mul_d.c,v $ */ 77 /* $Source$ */
78 /* $Revision: 1.3 $ */ 78 /* $Revision$ */
79 /* $Date: 2006/03/31 14:18:44 $ */ 79 /* $Date$ */